Draft attachment for excavating machines



H. S. KNIGHT DRAFT ATTACHMENT FOR EXCAVATING MACHINES Dec. '29, 1931. I

Filed Jan. 26, 1931 Patented Dec. 29, 1931 UNITED STATES PATENT-OFFICE F HERVEY S. KNIGHT, OF EVANSTON, ILLINOIS, ASSIGNOR TO AMERICAN MANGANESE STEEL COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF MAINE DRAFT nTrAoHMEn'r non EXCAVATING MACHINES Application filed January 26, 1931. Serial No. 511,124. g

This invention relates to an attachment that maybe applied to an excavating machine, such as a scraper, in which the digging effect is largely controlled by the point of attachment of the drag line. In implements-bf this kind it has been found desirable to render the point of attachment rigid vertically in order to produce the best effect in digging control; but it is also important to have the 1 0" draft attachment vertically adjustable for similar reasons, and haveit non-rigidunder forces encountered in directions traverse to the vertical. The present invention accomplishes all of the results stated, and in addition thereto renders the draft connection of constructing the draft appliance in the form of a draw bar mounted for rotation upon its longitudinal axis, deflected at its forward end to present its point of attachment for the chain or other flexible draft-connection sufiiciently offset to enable the offset portion to yield by rotation of the draw bar under impact transverse to the longitudinal axis; and the said draw bar having its mountings located to present its said longitudinal axis in a position which, while it may be located in any one of several planes coincident with the line of draft, isso inclined to the line of draft that while permitting its offset end to yield laterally under forces other than those of the draft,it will be held rigid by the tension of the draft against any movement having a vertical component, for the reason that any rotation of the draw bar causes the attaching end to move in a path that "increases the distance from the power that develops the draft; and the draw bar, while arrested at' a predetermined limit against movement in the outward direction .may move inwardly under an impactapplied M rearwardly to its attaching end, I thereby saving it from injury from forcesin the lastnamed "direction, a spring being preferably provided w yieldingly hold the draw bar in its foremost-position and absorb the shock of suchlrearwardi impact; The axial movability of the draw bar in its z'bearings is availed of to secure adjustment of the draw bar for changing the fixed height of its attachingend; this purpose beingatt-ained by threading upon the .draw bar the arresting shoulder that limits its o'utwzirdmovement, and the variation of height of the attaching point being developed through the very considerable vertical component enterlng into the diagonal position when i the axis of the draw bar is in a vertical plane, in addition to the fore-and-aft adjustment with increase of leverage relatively to the digging teeth by reason of the very con-' siderable fore-and-aft component in the position of'the draw bar. When the axes of the draw bars are in a horizontal plane, the fore-and-aft component, with corresponding variation of leverage over the digging teeth, will alone regulate the digging effect.

In the accompanying drawings:

Figure 1 is a side elevation of a typica drag line scraper to which thepresent invention is applied. 1 j

Figure 2 is a fragmentary view of the implement shown in Figure 1 and its draft attachment, on an enlarged scale.

Figure 3 is a detail sectional View on the line 300-3m ofFigureQ.

F'gure f is a view similar to Figure 1, bu ona reduced scale, showing a position of the draw bar in a vertical plane which includes the line of draft, but inverted from thepositions of-Figures 1 and '2; and

Figure 5 is a plan view of the implement showing the draw bars located with their axesin the horizontal plane of draft.

A re'presents a drag line scraper which may be of conventional designand which will preferably include a yoke B having an attaching ear C for the. lifting ';or control chain employed in the manipulation of the implement. At the draft point D of the scrap'er'A is mounted the draw bar 1 of the present invention, which is to be understood as being duplicated on opposite sides of, the

implement." This" draw bar is mounted in bearings 2 located to give to the longitudinal axisof the draw bar 1 a position which, while in a plane whichfalso, includes the line of draft, has a'componentwhich is at a very material angle less than 90 (for instance 45) to the line of draft; and the outer end of the draw bar is provided with a deflected arm 3 carrying the attaching eye 4 or other appropriate means through which to attach the draft connection, for instance, a drag line chain, one link of which is shown at 5. De flected arm 3 is of such length that it presents the attaching end 4 for the draft chain, one link 5 of which is shown, in a position materially offset from the longitudinal axis of the draw bar, with the result that when the draw bar rotates, which it is left free to do in its bearings 2, the eye 4 will follow a path which consists largely of a rearward component. That is to say, the eye will move rearwardly with respect to the force that is dragging the implement; hence, tension on the drag chain will prevent such rotation and will give to the attaching eye 4, so long as it is under tension, vertical rigidity at the point selected to cause the desired penetration of the digging teeth E of the implement. hen, however, the implement is picked up by a control connection attached to the ear C and cast outwardly to a position from which it is to gather its load, lateral impact against the arm of the draw bar 1 will not tend to bend the draw bar for the reason that the arm, now free from tension, can yield laterally. To save the draw bar from injury under impact in a direction having a rearward component, draw bar 1 is adapted to yield longitudinally inward in its bearings 2, since it is sustained at its outward limit by a shoulder 6 on the inner side of the forward bearing 2. For convenience, the draw bar may be held to its forward limit yieldingly by spring 7 introduced between shoulder 6 and the inner bearing 2.

It will be seen that the very substantial vertical component that enters into the direction of the diagonally positioned draw bar causes its attaching eye 4 to change its elevation by longitudinal movement of the draw bar, so that by having the shoulder 6 in the form of a nut engaging the threads 8, the limit of outward movement of the draw bar may be varied at will and a plurality of different elevations given to its eye 4, as suggested by full lines, broken lines and dotted lines in Figure 2. As the normal distance between the shoulder nut 6 and the inner bearing 2is constant, spring 7 is not affected by longitudinal adjustment of the draw bar.

It is not necessary in mounting the draw bar in a vertical plane and at a substantial angle to the line of draft in said plane, that the draw bar be inclined upward. As shown in Figure 4 it may be inclined downwardly and forwardly with results similar to those described with reference to Figures 1 and 2. In Figure 4, the draw bar 10. in bearings 21; will be provided with limiting nut 6a and offsetting arm 3a, as well as other accessories that may be desired, just as described in connection with Figures 1 and 2.

It is not indispensable that the draw bar be mounted in a vertical longitudinal plane of the implement. As shown in Figure 5, it may be mounted in a horizontal plane where draw bars 17) are fitted in bearings 2?) that give to them a position inclined horizontally to the line of draft, and having deflections 31) that offset the attaching points 46 laterally from the longitudinal axis of the'draw bar, with the same general effect as described in connection with Figures 1, 2 and 4 except that longitudinal adjustment of the draw bars, which may be effected through means of their nuts 6?), does not change the altitude of the attaching points 46, but it does change the leverage relatively to the digging teeth E through which the draft is exerted, and to this extent embodies the principle of adjust- :gbility by longitudinal shifting of the draw The angle which the longitudinal axis of the draw bar 1a or 1?) assumes to the line of draft, while effective when at 45 to the line of draft, may be varied so long as it is great enough to render the rearward component of the arcuate path of attaching point 4, 4a or 4?) sufficient to steady the position of the attaching point under the tension of the draft and not so great'as to defeat yielding of the draw bar in the direction of its longitudinal axis under a substantially rearward impact against the attaching end when not under tension.

I claim:

1. A draft connection for digging implements, comprising a draw bar mounted upon the implement with its longitudinal axis at a substantial angle but less than a right angle to the line of draft; said draw bar having an arm carrying an attaching means for a drag line, said arm extending at a substantial angle to said axis and thereby laterally olisetting said attaching means therefrom.

2. A draft connection as described in claim 1, in which the draw bar is provided with hearings on the implement in which it is rotatable about its longitudinal axis, and thereby renders the offset attaching means lateral- 3 1y yieldable.

3. A draft connection as described in claim 1, in which the draw bar is axially yieldable in a direction having a substantial rearward component.

4. A draft connection as described in claim 1, in which the draw bar is provided with bearings through which it is mounted upon the implement, and in which it is rotatable and also yieldable axially in a direction having a substantial rearward component.

5. A draft connection as described in claim 1, in which the draw bar is axially movable rearwardly and has means for yieldingly resisting such movement.

6. A draft connection as described in claim 1, in which the draw bar is adjustable in the direction of its longitudinal axis, and by said adjustment varies the control of the'line of draft over the digging of the implement.

7. A draft connection as described in claim 1, in which the draw bar is mounted in a vertical plane and is adjustable in the direc' tion of its axis to change the elevation of its attaching means and thereby vary the control of its draft over the penetration of the digging implement. i

8. A draft connection as described in claim 1, in which the draw bar is adjustable in the direction of its axis, is rearwardly yieldable in the direction of said axis, and is rotatable about the same.

9. A draft connection as described in claim 1, in which the draw bar is provided with. bearings through which it is mounted upon the implement with axial movement, and said draw bar is provided with an adjustable nut threaded upon it and constituting a shoulder limiting its forward movement in its said bearings.

10. A draft connection as described in claim 1, in which the draw bar is provided with bearings through which it is mounted upon the implement with axial movement, and said'draw bar is provided with an adjust able nut threaded upon it and constituting a shoulder limiting its forward movement in its said bearings; said draw bar also having a spring yieldingly pressing the said nut for ward.

11. A draft connection as described in claim 1, in which the draw bar is positioned with its longitudinal axis extending forwardly and upwardly in a vertical plane.

12. A draft connection as described in claim 1, in which the draw bar is positioned with its longitudinal axis inclined downwardly and forwardly in a vertical plane.

13. A draft connection as described in claim 1, in which the draw bar is positioned with its longitudinal axis extending forwardly but inclined to the line of draft of the implement in a horizontal plane.

Signed at Chicago, Illinois, this 16th day of January, 1931.

' HERVEY S. KNIGHT. 

